Dispatch radio communication systems are known to comprise a data router, a plurality of base stations or repeaters that provide a plurality of communication resources, and a plurality of console stations that control allocation of the communication resources to users of the dispatch communication system. Each console station is operated by a dispatch operator and typically includes a plurality of control modules. The communication resources typically comprise radio frequency carriers, time slots conveyed via radio frequency carriers, or telephone lines.
During installation of a typical dispatch communication system, each console station is provided with a programmable read only memory (PROM) that contains a predetermined list of communication resources, corresponding aliases for each communication resource, and a list of corresponding resource features employed by each communication resource. The list of communication resources includes those communication resources whose resource features can be supported by a particular control module. For communication resources other than telephone lines, the resource features might include the capability to receive data signals or decode an encrypted voice signal. For telephone resources, the resource features might include providing call hold or forwarding capabilities.
Each control module can control, or be assigned to, one of the communication resources in the communication resource list upon selection of the communication resource by the dispatch operator. To select the particular communication resource, the dispatch operator scrolls through the list of communication resource aliases, which may be quite lengthy, until the alias for the particular communication resource is identified. A communication resource alias is typically a code word or number that is associated with a communication resource. For example, a communication resource exclusively used by the fire department might be designated with the alias "Fire;" whereas, a telephone resource might be identified by its corresponding telephone number. Depending on the length of the communication resource list, the selection process might require several minutes to complete.
Although assignment of a control module to a communication resource using the scroll list approach results in an acceptable assignment, this approach often results in an inefficient assignment. As mentioned above, each communication resource typically employs a plurality of resource features, some of which are essential to function and others which are desired, but not essential to function. During assignment using the above approach, the dispatch operator can only view the communication resource aliases and cannot view the list of resource features for each alias. Accordingly, the dispatch operator arbitrarily assigns an available (i.e., unassigned) control module that can support the communication resource to be added to the communication resource. Since the dispatch operator cannot compare the list of resource features employed by the communication resource with the resource features that the assigned control module can support, the dispatch operator cannot determine whether or not the assigned control module is the control module that allows the most efficient use of the resource features employed by the communication resource (i.e., provides support for at least some of the the desired resource features). Thus, some assignments are inherently inefficient because control modules that support only the essential resource features of particular communication resources are assigned to those communication resources while other control modules, which support at least some of the communication resources' desired features, might be available.
Another dilemma encountered in prior art dispatch communication systems occurs when a change is required in the characteristics of the dispatch communication system. This change typically results from the addition of communication resources to the dispatch system. To accommodate a change in system characteristics, prior art techniques require the disabling of the console station whose control modules might be assigned to the additional communication resources, so that the console station can be installed with a new PROM and any other necessary hardware modifications (e.g., additional control modules). This hardware alteration process can result in considerable system down time. Accordingly, prior art dispatch communication systems are generally not conducive to operating environments requiring continual changes in system characteristics.
In addition to the problems associated with accommodating changes in system characteristics, existing dispatch communication systems are typically restricted in their ability to provide adequate support of telephone resources within their control modules. Prior art control modules that support telephone resources commonly include a permanent, single-tone ringer, similar to the bell ringer incorporated into most telephones. The ringer informs the dispatch operator of an incoming telephone call on a particular control module. However, since the finger is a permanently installed, single-tone finger, the ringer within a particular control module always rings with the same cadence and ring-tone, or pitch, regardless of which telephone resource is assigned to that control module. Thus, with prior art control modules, audible identification of a telephone resource that is assigned to a control module is highly improbable due to the limitations inherent in the single-tone ringer. For example, a high priority incoming call from a police chief is audibly indistinguishable from a standard incoming call.
Therefore, a need exists for a method and apparatus for assigning control modules to communication resources that substantially reduce the complexity of the assignment process and that accommodate changes in system characteristics. Further, such a system that provides tracking of a telephone resource's ring-tone and cadence with the telephone resource would be an improvement over the prior art.